Grass plant for shade/wet (Stanstead St Margarets SG12)

I recently dug up a clump of grass - I believe it is called Acorus gramineus. It seems to like shade and damp conditions (near ponds?). It has been in water and new shoots are emerging (see pictures) so definitely alive. I have divided it into about 10 bits but could be divided further and potted on/put directly in the ground. I have left it in a bowl outside my front door so can be collected whenever - enough for 3 or 4 freeglers. Please just let me know when you can collect so I can monitor how much is left for the next person. Cathy